Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 4

EASY

8th CBSE

IMPORTANT

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On subtracting $a^{3} + b^{3} + c^{3} - 3 a b c$ from $7 a b c - 3 a^{3} + 5 b^{3} - c^{3}$ we get $- 4 a^{3} + 4 b^{3} - 2 c^{3} + k a b c$ , find the value of $k$

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Important Questions on Algebraic Expressions and Identities

EASY

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 5

If we subtract $3 x - 7 x^{3} + 5 x^{2}$ from the sum of $2 + 8 x^{2} - x^{3}$ and $2 x^{3} - 3 x^{2} + x - 2$ .

We get $a x^{3} + b x$ then find the value of $a + b$ .

EASY

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 6

If we simplify the following expression we get $a^{2} + k a$ , then find the value of $k$ .

$4 a - 2 a^{2} - (2 a - 3 a^{2})$

MEDIUM

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 6

Simplify the following.

$3 x - 4 y - (3 y + x) - (5 x - 8 y)$

MEDIUM

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 7

If

k a^{2} b - 14 a b^{2} + a^{3} b^{3} + b^{4}

is added to

10 a^{2} b + 8 a b^{2} - 8 a^{3} b^{3} - b^{4}

to get

5 a^{2} b - 6 a b^{2} - 7 a^{3} b^{3}

, then find the value of

k

.

EASY

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 8

If

3 x^{3} + k x^{2} y - 10 x y^{2} + y^{3} - y

is subtracted from

8 x^{3} + 7 x^{2} y - 3 x y^{2} - y

to get

7 x y^{2} - y^{3} - 3 x^{2} y + 5 x^{3}

then find the value of

k

.

MEDIUM

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 9

Find the perimeter of a rectangle whose adjacent sides are

3 x - 5 y - 4 z

and

x - 3 y + 5 z

EASY

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 10

The perimeter of a triangle is

5 x^{2} + 3 x - 1

and two of it's sides are

2 x - 5 + 7 x^{2}

and

3 x^{2} + 4 - 2 x^{3} + x

. If the third side of the triangle is

a x^{3} + b x^{2}

, then find the value of

a + b

.

MEDIUM

8th CBSE

IMPORTANT

Number Magic a textbook of Mathematics 8>Chapter 16 - Algebraic Expressions and Identities>EXERCISE>Q 11

A boy works

(x + y)

sums of which only

y - 2 z

are right. How many are wrong?